Abstract: The present work tests the use of carapace fragments of the marine turtle Caretta caretta as a tool for environmental biomonitoring of mercury (Hg) and to evaluate the influence of biological and ecological factors in Hg concentrations. Samples of carapace fragments were obtained during the nesting season of 2012 and 2016 and were analyzed for their total-Hg and methyl-Hg concentrations and the isotopic composition of carbon and nitrogen (δ15N and δ13C). Seventy-six females were sampled, with an average size of 87.1 to 107 cm of curved carapace length (CCL). The results showed a wide variation in total Hg concentrations (3.3 – 1,672 ng g-1) and low concentrations of methyl-Hg, not showing any pattern of accumulation among the individuals. The isotopic composition of δ15N and δ13C suggests that the individuals sampled belong to a high trophic level but did not present any relationship with the Hg concentrations. It suggests that, at least with the existing results, and unlike other turtle species, carapace fragments of C. caretta cannot yet be used in environmental monitoring.

The gold mining in the Madeira River basin is performed by dredges and ferries that extract from the bottom of the river alluvial gold which is amalgamated with mercury (Hg). Throughout the process of gold purification, the Hg can be recovered by retort or crucible distillation. Subsequently, the gold is taken to the city of Porto Velho for commercialization, once more being smelted with blowtorch for jewelry making. This study aims to evaluate the Hg concentration exposed in the atmosphere of gold shops via an atomic absorption spectrophotometer coupled to portable cold steam generation (LUMEX) and to determine the occupational exposure through the analysis of urine samples of gold shops workers. Eleven gold shops and twenty workers were investigated. Some risky situations which may accompany the health of employees, such as poor ventilation, lack of exhaust systems and unhealthy places, have been verified in loco. The results showed atmospheric concentrations of Hg above the limits established by WHO, which is at most 200 ng m-3 in four gold shops. All examined presented total Hg results in the urine below the occupational limit of (50.00 μg L-1).

Knowing the mercury levels of an environment allows a diverse array of biogeochemical studies into the mercury cycle on a local or global scale. Among matrices commonly evaluated, water remains a challenge for research because its mercury levels can be very low, requiring development of complex analytical protocols. Currently, sample preservation methods, protocols that avoid contamination, and analytical techniques with low detection limits allow analysis of mercury in pristine waters. However, different protocols suggest different methods depending on a range of factors such as the characteristics of water sampled and storage time. In remote areas, such as oceanic and Amazonian regions, sample preservation and transport to a laboratory can be difficult, requiring processing of the water during the sampling expedition and the establishment of a field laboratory. Brazilian research on mercury in water can be limited due to difficulty obtaining reagents, lack of laboratory structure, qualified personnel, and financial support. Considering this complexity for analyzing water, we reviewed methodologies for sampling, preservation, and storage of water samples for analysis of the most commonly evaluated mercury species (dissolved gaseous mercury, reactive mercury, methylmercury and total mercury).

Foram estudadas as alterações na hidroquímica e na distribuição de Hg em águas do Rio Madeira entre Porto Velho (RO) e a confluência com o Rio Amazonas (AM) em dois cruzeiros realizados em 1997 e 2002. A condutividade da água foi similar nos dois períodos, porém o pH foi significativamente maior em 2002, principalmente ao longo da porção média do curso do rio. A concentração do material suspenso total também aumentou de 1997 a 2002, nesta mesma porção do rio, o que é um resultado da conversão de florestas para outros usos, principalmente pastos e agricultura, que foi intensificada no intervalo entre os dois cruzeiros. As concentrações de Hg dissolvido foram similares ao longo do rio nos dois cruzeiros, mas as concentrações de Hg particulado aumentaram significativamente ao longo da porção média de seu curso, embora em 2002 a concentração de Hg no material particulado fosse menor que aquela verificada em 1997. Uma vez que o Hg particulado representou mais de 90% do total do Hg presente na água, ocorreu um aumento significativo no transporte de Hg total pelo Rio Madeira. Embora o garimpo de ouro tenha praticamente cessado na região, a remobilização de Hg pela conversão de solos florestais para ouros usos é responsável pela manutenção de níveis relativamente elevados de Hg no meio ambiente do Rio Madeira.

Changes in hydrochemistry and Hg distribution in the Madeira River from Porto Velho to the confluence with the Amazon River were studied in two cruises in 1997 and 2002. Water conductivity was similar in both periods, but the pH was significantly higher in 2002, in particular along the middle reaches of the river. Total suspended matter concentrations also increased from 1997 to 2002 along the same river portion, which is a result of forest conversion to other land uses, in particular pastures and agriculture accelerated during the interval between the cruises. Dissolved Hg concentrations were similar along the river in both cruises, but particulate Hg concentrations increased significantly along the middle portion of the river, although the suspended matter from 2002 was relatively poorer in Hg compared to that from 1997. Since particulate Hg represents more than 90% of the total Hg present in the river water, there was a significant increase in the total Hg transport in the Madeira River. Although gold mining has nearly ceased to exist in the region, the remobilization of Hg from forest soils through conversion to other land uses is responsible for maintaining relatively high Hg content in the Madeira River environment.

The goal of this research was to evaluate the biodegradation of diesel by a microbial consortium collected in a region close to distributors of fuel. The experiments were monitored by SPME-GC-FID and SPME-GC-MS. The consortium showed a high potential for production of biosurfactants, presenting an emulsification index of 53%. The consortium degraded completely n-alkanes, while dimethylnaphtalene, hepthyl-cyclohexane and 2,6,10-trimethyl-undecane were partially degraded and pristane was not degraded. From this consortium five strains were isolated and identified as Acinetobacter baumannii. Based on this initial investigation this consortium appears to be effective for bioremediation in Porto Velho - RO region.

Tucker-3 model offers several advantages for analysis of environmental data but its interpretation is still challenging. A Tucker-3 model was applied to a biodegradation experiment involving a large number of overlapped chromatographic peaks and a temporal variation. The Tucker-3 model allowed the data to be decomposed in two processes: evaporation and biodegradation. The results suggest that linear hydrocarbons were those biodegraded first and demonstrate that the data analysis can be simplified by interpreting the elements of the core array. The approach discussed in this work can be applied in similar problems involving multi-way data in other areas of chemistry.

DDT concentrations had been quantified in fishes and at 20 points along the "Puruzinho" lake. The determination of pollutants in the samples consisted in four consecutive steps: extraction, clean-up, fractionation and automatic injection in high resolution gas chromatography coupled to an electron capture detector. The ΣDDT results in fishes (ng g-1 dry weight) ranged from 0.3 to 71.4. The concentrations of ΣDDT on house soils varied from 2.0 to 55.4 ng.g-1 while forest soils the obtained values were between 1.6 e 13.3 ng g-1. The Shapiro-Wilk test showed that the distribution was not normal for both the results of the soil of the houses (p < 0.001) as well as for the forest soils (p < 0.007). The U test of Mann-Whitney reveled that there were no significant difference between the results obtained for both houses and forest soils (p > 0.290).

O inseticida organoclorado DDT foi largamente utilizado no Brasil desde 1945, para fins agrícolas e no controle de vetores. Em 1986 foi proibida a sua utilização na agricultura e em 1997 esta proibição se estendeu também ao uso no controle de vetores. No entanto, a presença de DDT no meio urbano, solos florestais, leite materno e biota aquática ainda é comum especialmente na Amazônia. Os resultados obtidos desde meados dos anos 90 indicam que a contaminação ambiental com este pesticida ainda é relativamente alta. Devido ao elevado consumo de peixe pelas populações ribeirinhas tradicionais, o leite materno pode representar uma importante fonte de exposição ao DDT para os recém-nascidos. Novos resultados sobre DDT e PCB no golfinho vermelho (Inia geoffrensis), um mamífero aquático endêmico da Amazônia, também é relatada.

The organochlorine insecticide DDT was extensively used in Brazil since 1945, both for agricultural purposes and for vector control measures. In 1986 its uses were forbidden in agriculture and in 1997 it was also phased-out in vector controls programs. However, the presence of DDT in urban and forested soils, breast milk and aquatic biota is still common, especially at the Amazon region. The results gathered since the middle of the 90s indicate that environmental contamination with this pesticide is still relatively high. Due to the high fish consumption by traditional riverside populations, human breast milk may represent an important source of DDT exposure to newborns. New results on DDT and PCBs in red dolphin (Inia geoffrensis), an endemic aquatic mammal of the Amazon region, is also reported.